The present invention relates to adhesive tape structures that can be adhered to a surface and thereafter removed without substantially damaging the surface or leaving substantial adhesive residue. More particularly, the present invention relates to a removable and separable adhesive tape product.
Many types of adhesive products have been developed which permit the separable connection of plural objects. For example, laminated tape structures have been used to bond the opposed surfaces of two objects together, such as to bond a wall hanging (e.g. a poster, plaque or picture) to the surface of a wall.
In order to permit a separable connection, the adhesive product may comprise an easily releasable adhesive permitting removal from a substrate surface while leaving little or no adhesive residue on the surface. Examples include repositionable products available under the trade designation xe2x80x9cPost-itxe2x80x9d from Minnesota Mining and Manufacturing Company (xe2x80x9c3Mxe2x80x9d) of St. Paul, Minn.
Another type of removable adhesive tape laminate is a single-sided or double-sided adhesive tape that is stretchable to accomplish removal. Such an adhesive tape can have conventional pressure-sensitive adhesive on one or both major surfaces thereof, and a tape backing comprising a highly extensible material. Alternatively, the adhesive may comprise a solid adhesive material that itself provides one or two adhesive surfaces and is sufficiently extensible. These tapes are often referred to as stretch release adhesive tapes because when the backing or solid adhesive layer is stretched after the tape is adhered on one or both sides, the adhesive stretches and undergoes clean interfacial debonding from the substrate or substrates to which it is adhered. Moreover, such stretch release adhesive tapes are known to be provided in strips for bonding objects together and which have a pull tab portion at the end of the strip to facilitate the stretching and debonding. Examples of such strips and tabs are described in U.S. Pat. No. 5,409,189 to Luhmann and U.S. Pat. No. 5,516,581 to Kreckel et al, and in U.S. patent application Ser. Nos. 08/308,937 entitled xe2x80x9cRemovable Foam Adhesive Tapexe2x80x9d filed Sep. 20, 1994 and 08/940,555 entitled xe2x80x9cRemovable Adhesive Tape with Controlled Sequential Releasexe2x80x9d filed Sep. 30, 1997, both to Bries et al. An article support specifically designed for use with such stretch release tapes is disclosed in U.S. Pat. No. 5,507,464 to Hamerski et al. An advantage of these stretch release adhesive tapes is that they utilize conventional pressure sensitive adhesives that can provide a strong bond against shear, peel and lift-off forces. Moreover, heavier weighted objects can be supported.
With these stretch releasable tape strips, access must be provided to the tab to permit the release. In the case where the strip is provided between an object support, e.g. a picture hook, and a surface, e.g. a wall, the tab can be provided easily where the support and exposed tab will be covered by the object (such as a picture) to be supported thereon. Also, with object supports, such as a picture hook, the hook can be reusable by providing a new tape strip. If, however, it is desirable to directly connect an object (such as a picture) to a substrate (such as a wall) by a stretch releasable strip, the tab needs to extend out from between the opposed surfaces to provide access. In many cases, this can provide an objectionable appearance.
To overcome this problem, a tape laminate structure has been developed having an internally separable layer, which is described in co-pending U.S. patent application Ser. No. 08/746,351 entitled xe2x80x9cInternally Separable Tape Laminatexe2x80x9d filed Nov. 8, 1996. A tape structure is provided that can be used to bond together the opposed surfaces of objects with no portion of the tape structure projecting from between the objects and which permits separation of the objects. The tape structure comprises an internally separable layer provided between one or two stretch releasable tape strips. By this construction, the objects can be first separated from one another by applying a force substantially perpendicular to the surface direction of the tape lamina causing the internally separable layer to break within itself. That is, a portion of the layer stays attached to one object while another portion of the internal layer stays with the other object Then, with the objects separated, each layer portion can be removed from its respective object by pulling a stretch release tab. Since the stretch release tabs are only needed after separation of the internal layer, they can easily be positioned to be hidden when the objects are secured together. However, once the objects are separated from another, which causes the internal layer to be broken apart, the objects cannot be reconnected with one another unless a new separable tape structure (or other type of product) is used.
Reusable connectors of many types are also commonly known, with particular types being more suited for specific different applications than others. Reusable fasteners include mechanical type fasteners, such as hook and loop systems (e.g. hook and loop products available under the trade designation xe2x80x9cVelcroxe2x80x9d and those commercially available under the trade designation xe2x80x9c3M Scotchmatexe2x80x9d industrial fastener, from Minnesota Mining and Manufacturing Company (xe2x80x9c3Mxe2x80x9d) of St. Paul, Minn.), other mechanical interlocking fasteners, such as described in U.S. Pat. No. 5,077,870 to Melbye et al, and intermeshing fasteners (having connection without macroscopic mechanical deformation or interference), such as described in U.S. Pat. No. 4,875,259 to Appeldorn.
Other reusable fasteners include releasable contact responsive fasteners, such as described in PCT International Publication No. WO 94/21742 or PCT International Publication No. WO 96/24535. Contact responsive fasteners include a non-tacky layer and a target layer to which the non-tacky layer can bond. Contact responsive polymer layers are more readily able to bond to materials having similar solubility parameters, and when the solubility parameters of the target layer and the contact responsive polymer layer are sufficiently close, the degree of interaction between these materials is enhanced and bond formation is promoted.
Many reusable fastener systems are also known to be provided with adhesive on their respective non-connector side surfaces for bonding to the objects which are to be connected. For example, the hook side of a hook and loop system may be adhered to one object while the loop side is adhered to another object. Although these fastener systems permit the separation of one object from another, each of the objects retains its portion of the fastener system, which are not easily removable.
The present invention overcomes the disadvantages and shortcomings of the prior art by providing an adhesive tape construction that is removable from one or more objects to which it is adhered and which is reusably separable within its construction so that an object can be separated from another and subsequently reconnected with one another. Thus, the present invention provides an adhesive tape construction that can be used to bond the other opposed surfaces of objects, including rigid objects such as a picture frame to a wall, where no portion of the adhesive tape construction projects from between the objects, and which subsequently affords easy separation of the objects without damage to either of them. More specifically, the adhesive tape construction includes a stretch release adhesive tape structure combined with a reusable connector surface.
The aforementioned advantages are achieved by an adhesive tape for attaching plural objects to one another, the tape comprising at least one stretchable backing layer having first and second major surfaces and first and second ends, an adhesive surface over at least a portion of the first major surface of the backing layer for bonding to a surface of an object, and a separable connector surface covering at least a portion of the second major surface of the backing layer. The backing layer and adhesive surface may be provided by a single solid adhesive layer or may comprise a separate backing layer combined with an adhesive layer. By this construction, the backing layer and adhesive surface (provided by separate layers or as a solid adhesive layer acting as both) are stretchable together to effect progressive debonding of the adhesive layer from an object after the adhesive surface is bonded to that object by the application of a force to the first end of the backing layer in a direction of extension of the backing layer between its first and second ends. Moreover, the separable connector surface possesses the ability to be connected, disconnected and reconnected to a cooperating connection surface without destruction of the separable connection surface and/or the adhesive tape.
Preferably, a second backing layer is also provided having first and second major surfaces and first and second ends, an adhesive surface over at least a portion of its first major surface for bonding to a surface of another object, and a cooperating separable connector surface covering at least a portion of the second major surface of the second backing layer. The second backing layer and adhesive surface may be provided by a single solid adhesive layer or may comprise a separate backing layer combined with an adhesive layer. Again, the second backing layer and its adhesive surface (provided by separate layers or as a solid adhesive layer acting as both) are stretchable together to effect progressive debonding of the adhesive surface from the other object after its adhesive surface is bonded to that object by the application of a force to the first end of the second backing layer in a direction of extension of the second backing layer between its first and second ends and the cooperating separable connector surface possesses the ability to be connected, disconnected and reconnected to the connection surface of the first backing layer without destruction of the separable connection surface, the cooperating connection surface and the adhesive tape.
The separable connection and cooperating separable connection surfaces can be provided in any number of different ways depending on the particular application and the desirable characteristics for that application. Interlocking mechanical connector systems, intermeshing connector systems, contact responsive fasteners, magnet, and low-tack adhesives are but a few examples of suitable connector systems.
The present invention is also directed to the combination of the aforementioned tape constructions with a plurality of objects. The tape construction is particularly applicable for the joining of an object to a vertical surface (for example, a picture frame to a wall), but can be used in any number of bonding applications.